I was having the same trouble as you, but here is what I did: I make the quilt sandwich and then cut away the right hand third of the batting only. Use a wavy cut lineand label the top of both pieces of batting. That way you can easily replace the cutout batting when its time. Meanwhile, quilt the center third. You will not have the batting in the throat of your machine as you have cut it out. Turn around and quilt the right side of the quilt. Now, replace the cutaway batting. Whip stitch it exactly in the same place it was before you cut it away. Now you can quilt this third. Easy peasy!